Brake mechanism and cooling structure therefor

ABSTRACT

A brake, particularly adapted to stop feeder rolls of a paperboard partition assembly machine quickly, of the drum and embracing arms type, the two brake arms spring-urged into contact with the drum, with cam-operated means for separating brake shoes from the drum; there being cooling means for the brake including integral air-cooling ribs projecting from the brake arms, and air pressure means having two circumferentially and axially spaced outlets on each brake arm to direct air through the brake arm and the brake lining to the outer surface of the drum both to cool the outer parts of the drum and to clean the outer surface, the outlets being automatically cut off when the brake is in braking position, and there are air-circulating fins on the brake drum that draw air across the inner parts of the drum.

BACKGROUND OF THE INVENTION

Heretofore, as in the U.S. Pat. No. 3,200,910, in the name of Cunninghamand Engle and the references cited therein, brakes of the presentgeneral type have been disclosed. This type usually includes at leastone, and preferably two, arcuate brake arms pivoted on one side of thedrum, extending around to the other side and spring-urged together toapply friction to the drum, and means to separate the arm to release thedrum. In the cited prior art it is pointed out that it is important thatthe feed wheels of partition assembling machines stop quickly where astep, such as a cutting step, is to be performed on the material beingfed. If the brake does not stop the feed rolls quickly, the paper may becaused to over-run or back up, ultimately resulting in a partition ofirregular size.

The present improvement consists in novel air cooling means for thebrake, so that the brake is air cleaned and is air cooled both on itsouter and inner parts. The brake drum is provided with fins between theshaft and the cylindrical rim, with air ports adjacent the fins, so thatas the drum rotates, air is drawn inside the rim to cool the insideparts of the drum. Then also there are longitudinal cooling fins on eachbrake shoe, and with two circumferentially spaced compressed air outletsfor each brake arm: one outlet in the upper part and the other outlet inthe lower part of each. Furthermore, one outlet is on one side of thecooling fin or rib, and the other outlet on the other side. Thisarrangement gives not only a more complete cleaning of the rotatingbrake drum, but also a more complete cooling of the outer parts of thedrum and the shoes.

Another feature of the invention is that the brake operation itself isemployed as a cutoff valve so that it is unnecessary to add externalcutoff valves and the timing mechanisms that would be required to causethe air to flow at the proper time.

Also an improved arrangement for operating the brake arms has beenprovided which simplifies the operation and reduces the number of partsrequired.

In the drawings:

FIG. 1 is a front elevation of the brake of the present invention, theoperating parts being shown somewhat diagrammatically;

FIG. 2 is a vertical section through the middle of FIG. 1;

FIG. 3 is an enlarged section on the line 3--3 of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the description to follow, the details of the partition assembler andstripper will not be given because of the information given in U.S. Pat.No. 3,200,910.

Here the brake sub-assembly includes a mounting plate 10 to be mountedupon an assembler and stripper 11 as by capscrews 12. The mounting plate10 has an opening 13 through it to receive a driving shaft 14 onto whichis mounted a brake drum 15 and to admit air flow. The brake drum 15 issecured to the shaft by appropriate means and is keyed thereto as at 16.It will be understood that the shaft 14 and hence the drum 15 rotateswith the feed wheels.

The mounting panel 10 has another hole 20 in its upper part, throughwhich a stud shaft 21 is mounted. This shaft is here shown as having athreaded end that receives a hex nut 22 that can draw a flange 23 on theshaft into a clamping relationship with the mounting panel 10. The shaft21 extends beyond the flange 23, and on its outer end it receives awasher 25 held in place by a cap screw 26. Between the flange 23 and thewasher 25 two brake arms 29 and 30 are rockably mounted on the shaft.They are complementary in shape.

The arm 29 has a bifurcated upper end, comprising mounting ears 31 and32 that are rockably mounted on the shaft 21 adjacent the flange 23,with an appropriate bushing. They embrace a similar mounting ear 34projecting from the upper end of the other arm 30, and also rockablymounted on the shaft 21.

As is evident from FIG. 1, the two brake arms extend downwardly in amore or less semi-circular manner so that between them they embracesubstantially all of the brake drum 15. Each is cut out in an arcuatemanner and is provided with a brake lining of approximately 180 degreesas shown at 35. Thus when the two brake arms 29 and 30 are squeezedtogether, they force the brake linings 35 against the drum for brakingaction.

The two arms extend downwardly from the drum in spaced relation to givetwo spaced projecting arms 41 and 42 that are generally parallel. A pin43 passes through the two arms. On one end it has a flange 44 retaininga coil spring 45 between the flange and the arm. At its other end it isthreaded and has a nut-lock nut arrangement 46 that confines anothercoil spring 47 between appropriate washers and the arm projection 42.These two springs are compression springs and normally urge the twobrake arms into braking relationship with the drum. The lock nuts 46 canbe adjusted to change the compression of the brake shoes on the drum.

The two arms 41 and 42 separate below the pin 43 and provide twosomewhat more separated downward projections 49 and 50. Each of thesereceives a threaded pin 51 having lock nuts 52 and 53 by means of whichit can be adjustably positioned and firmly secured in adjusted positionon its brake arm. Also each includes at its outer end a bifurcatedfitting 54 that holds a roller 55. The two rollers face each other andare normally separated when the brake arrangement is set up.

A brake-actuating arm 60 is pivoted at 61 to some appropriate part ofthe framework of the machine so that it can move its tapered point orwedge 63 upwardly or downwardly. This wedge can project between the tworollers 55 when it is moved upwardly, separating them so that the brakeis released. The point in the upward movement at which each brake shoeis released, can be adjusted by adjusting the nuts 52, 53, and theamount of separation of each shoe from the drum.

A cam 65 is mounted on a shaft 66 appropriately supported on the frameof the machine. This cam turns and causes the foregoing motion of thearm 60 in an upward direction, downward movement of the arm beingnormally effected by the springs 45 and 47.

As shown in FIG. 1 particularly, each of the two brake arms 29 and 30 isprovided with a cooling fin or rib 70. These cooling ribs extendcircumferentially, generally medially of the two arms. They increase thearea for delivery of heat to the surrounding atmosphere. In addition,specific air-cooling means are provided. They are the same for each ofthe two brake arms, so only one need be described.

A fitting 75 can be connected to a source of air under pressure. Itintroduces this air to a T 76 that is connected by a nipple 77 into thebrake shoe on one side of the rib 70. A hole 73 (FIG. 3) is drilledthrough the brake arm and the brake lining. Usually this is done in situto obtain proper alinement between the hole sections in the arms andlinings. Hence it must be drilled through the T 76 and later plugged at74.

With appropriate fittings 78, a tube 79 is also connected to the T 76.This tube 79 leads to a fitting 80 connected to a T 81 that is connectedby a nipple 82 to the brake arm 29, in this case on the side of thecooling rib 70 opposite to the connector 77. Again this brake arm andbrake shoe are drilled through so that air may be conducted to the drum,and the T is plugged at 83.

A further means is provided for cooling the inner parts of the brake andfor maintaining a cooling action during rotation of the drum. Thisconsists in forming the brake drum 15 with fins that can draw airthrough air passages in the drum as the drum rotates. The drum 15 has ahub 90 that projects backwardly from the rim of the drum, and alsoprojects forwardly inside the drum, being cut away to provide asemicylindrical overhang inside the drum. The hub 90 surrounds the shaft14 and is keyed thereto, as previously indicated, by the key 16 whichengages in a slot in the internal surface of the hub 90. When the drum15 is fitted onto the shaft 14, it is secured against axial movement onthe shaft by a semi-circular cap 92 that is held by cap screws 93 ontoan overhanging complementary portion of the hub 90. Access holes extendthrough the rim opposite the screws, to receive a screw driver forengaging and disengaging the screws.

The hub 91, other than the cap 92, is preferably formed as a singlecasting having a radial web 95 connecting the outer cylindrical drumportion 96 to the hub 90. The web 95 has a plurality of air ventopenings 97 around it, and in front of each opening 97 there is anangularly-disposed fin 99. Four such fins are illustrated. In FIG. 2,for clarity, the top and bottom fins are shown full, althoughtechnically they would be cut through at the diameter line. The fins 99extend integrally forwardly from the web 95 and terminate near the frontend of the drum viewed from the position of FIG. 1.

The inner edges of the fins, toward the axis, are shaped to accommodatethe presence of the removable bearing cap 92. The fins are also locatedand shaped so that they do not interfere with inserting or removing thescrews 93 that hold the bearing cap in place.

OPERATION

When the shaft 14 is properly rotating, it must be free of the brakingaction. This means that the arm 60 must have raised the wedge 63 toengage the two rollers 55 and spread the arms 29 and 30 to withdraw thebrake linings 35 from the drum.

Withdrawal of the linings 35 from the drum surface effects a cooling andcleaning of the outer parts of the brake. The action permits air flowthrough the fittings 75, thence it passes through the nipples 77, thencethrough the pipes 79 and the nipples 82. It emits from the holes such as73, coaxial with the two nipples, to impinge upon the rotating drum.

It will be noted that the two nipples in each case are circumferentiallyand axially spaced from each other so that each side of the drumreceives air at points about 180 degrees apart. This air cools bothsides of the outer parts of the drum and shoes, and also should be givenenough velocity to clean the drum. This last feature is of particularimportance because of the possibility of the accumulation of dust andother particles such as worn away brake lining particles resulting fromthe operation of the machine, which would interfere with theeffectiveness of the braking action and perhaps permit brake slippage.

It is also important that the air is cut off automatically in thisarrangement. Whenever the brake is applied by the springs 45, thelinings fit closely against the drum 15 in such wise as to preventsignificant escape of air. Therefore, outside valving and timingmechanism is unnecessary. There is thus automatic timing between theaction of the cam 65 and the air delivery, it being understood that theshaft 66 is keyed keyed to the operation of the feeding rolls of themachine.

Further, during operation of the machine, a further cooling action takesplace, that is particularly applied to the inner parts of the brake. Thefins 99 rotate with the drum, and draw air in from the back of thebrake, through the ports or holes 97 in the web of the drum, thenceforward and out the front of the brake. This flow of air dissipates heatduring rotation of the drum, and is particularly effective on the innerparts of the rim and drum.

Various changes and modifications may be made within this invention aswill be readily apparent to those skilled in the art. Such changes andmodifications are within the scope and teaching of this invention asdefined by the claims appended hereto.

What is claimed is:
 1. In a brake mechanism for industrial machineryrequiring properly coordinated and accurate braking of intermittentlyoperating shafts, wherein there is a shaft-driven brake drum and brakingmeans on only one surface thereof; the braking means including a brakearm pivotally mounted to extend around the brake drum and having anarcuate shape to receive a brake lining portion engageable with thedrum; means to urge the brake arm toward the drum to produce engagementof the brake lining with the drum, to bring the drum from a runningcondition at least substantially to a stop by sliding friction, thebrake arm being withdrawable from the drum to permit free rotationthereof; cooling gas conducting means having a gas output in the brakearm with a duct leading the gas through the brake arm and the brakelining so that it may impinge upon the drum whenever the brake arm andlining are removed from the drum, the duct opening into the brakingsurface of the lining in a brake drum-contacting portion thereof, andterminating short of the sides of the said portion, so that it iseffectively closed off whenever the braking means is in brakingengagement with the drum, the opposite side of the drum beingcontinuously exposed to the atmosphere.
 2. In the brake mechanism ofclaim 1, the brake arm being on the outside of the drum, the gas conduitmeans including outlet means leading through the brake lining in brakedrum-contacting portions thereof, to conduct the gas to outside of thedrum to cool the same, and fan-like fin means inside the drum to directair across the inside parts of the brake.
 3. In the brake mechanism ofclaim 2, with two gas outlets laterally displaced in the directioncoaxially with the drum so as to impinge air on different axially-spacedparts of the drum surface, both outlets terminating within the laterallimits of the brake drum conducting portion of the lining.
 4. In thebrake of claim 3, the brake arm having a cooling fin extending mediallythereof and the gas conducting means being present in each arm and beingarranged to project cooling gas on two different axially-spaced parts ofthe drum on opposite sides of the cooling fin.
 5. In the brake of claim1: additional means to control flow of cooling air over the drum, thedrum having a cylindrical flange against the outside of which the brakelining may engage, and mechanism to apply a current of air inside theflange in addition to the previously-mentioned cooling gas, the saidmechanism comprising fan-type fins on the drum inside its flange, thatproduce air flow inside the flange during rotation of the drum.